The oxidation of surface layers during reactive ion etching of GaAs in CF Cl qO and O plasmas

The RF plasma was created in a plasmatron system with accelerating potential of 20–700 V, discharge power of 0.5–5.0 Wrcm2 and at pressure of 10y4–10y2 Torr. The thickness and composition of formed oxide layer is considered experimentally at various etching parameters: ion current density, plasma composition, substrate temperature. The experimental curves were modeled by proposed phenomenological model. The model includes the main processes taking place during reactive ion etching: sputtering, adsorption, heterogeneous chemical reactions, desorption of volatile compounds and radiation enhanced diffusion. The model gives the kinetics of elemental composition on the surface and the composition of the altered layer. q1999 Elsevier Science B.V. All rights reserved